Systems and methods of legibly capturing vehicle markings

ABSTRACT

A system and method for legible capture of vehicle identification data includes video cameras and a computer. Recording attributes such as gain, gain shutter speed, and white balance are adjusted throughout ranges to maximize the likelihood of capturing at least one frame in which characters, such as those on the license plate, are legible. Successful capture of a legible frame may trigger storage of the data, while unsuccessful capture may trigger additional scans.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/269,144, filed Sep. 19, 2016, the disclosure of which is incorporatedherein by reference.

BACKGROUND 1. Field

Embodiments of the invention are broadly directed to legible videocapture of license plate data. More specifically, embodiments of theinvention record video of a scene using systems and methods thatincrease the likelihood of capturing at least one frame in which alicense plate or other identifiable vehicle marking is legible.

2. Related Art

Mobile recording systems, such as car-mounted cameras, serve manypurposes for law enforcement officers and other first responders, suchas documentation of events, collection of evidence, and improvement oftraining. One important function of recording systems used by lawenforcement is the capture of license plate data. Capturing licenseplate data or other markings of a vehicle, suspect, victim, bystander,fellow officer, or a scene's surroundings may be key in proving guilt orinnocence or locating parties of interest. Of course, to be of use insuch matters, written characters (e.g., numbers, letters, punctuation,logos, hazardous waste symbols, symbols) captured in recorded images,such as a license plate, must be legible. In many situations, legiblevideo capture of license plate data and other vehicle markings or scenesurroundings is made difficult by factors such as high motion, darkness,and/or interference from sources such as light, smoke, or fog.

Typical systems and methods for license plate recognition attempt toimprove legibility of license plates through improved illumination ofthe scene. Improving illumination requires bright lights that may becostly, distracting, power consumptive, ineffective, and/or logisticallydifficult to implement quickly. Other systems perform advancedprocessing to improve captured images but may be expensive, slow, andrequire very high processor dedication. What is needed is an improvedsystem and method for video capture of legible license plate data andother vehicle markings or scene surroundings that does not requireadditional or enhanced illumination of a scene.

SUMMARY

Embodiments of the invention provide systems and methods for legiblycapturing license plate data using a video camera. A first embodiment ofthe invention is directed to a method of scanning for a legible markingon a vehicle using a video camera with two or more recording attributes.Upon acquiring an indication to begin a scan with a video camera, afirst recording attribute is adjusted within a first scan range, betweena first lower limit and a first upper limit. Thereafter, a secondrecording attribute is adjusted within a second scan range, between asecond lower limit and a second upper limit. A portion of the scan thatincludes a legible marking on a vehicle is stored in a memory associatedwith the video camera or otherwise accessible by the video camera.

A second embodiment of the invention is directed to an image capturesystem including a video camera with at least a first recordingattribute and a second recording attribute, a storage device, and aprocessor. The processor is configured to adjust a first recordingattribute within a first scan range between a first lower limit and afirst upper limit, adjust a second recording attribute within a secondscan range, between a second lower limit and a second upper limit, andstore in memory a portion of the scan that includes a legible marking ona vehicle.

A third embodiment of the invention is directed to a method of scanningfor a legible marking on a vehicle using a video camera with two or morerecording attributes. Upon acquiring an indication to begin a scan witha video camera, a first recording attribute is adjusted within a firstscan range, between a first lower limit and a first upper limit. Next, asecond recording attribute is adjusted within a second scan range,between a second lower limit and a second upper limit. Thereafter, adetermination is made as to whether or not a marking on a vehicle hasbeen legibly captured. Based on this determination, further steps mayoccur, including initiation of additional scanning or storage of aportion of video data.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Each of theabove embodiments may include further recording devices, hardware, orsteps not explicitly described. Other aspects and advantages of theinvention will be apparent from the following detailed description ofthe embodiments and the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1A is a diagram of elements comprising embodiments of theinvention;

FIG. 1B is a further diagram of elements comprising embodiments of theinvention;

FIG. 2A is an illustration of an ideal clear image of a vehicle withlegible markings thereon;

FIG. 2B is an illustration of a clear image of a vehicle with a licenseplate having illegible markings;

FIG. 2C is an illustration of an unclear image of a vehicle with alicense plate having legible markings;

FIG. 3 is an illustration of a display of embodiments of the inventionfor presenting representative images of a license plate and solicitinguser response;

FIG. 4 is a first flow diagram of steps that may be performed inembodiments of the invention;

FIGS. 5A, 5B, and 5C illustrate a second flow diagram of steps that maybe performed in embodiments of the invention; and

The drawing figures do not limit the invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION

The following detailed description references the accompanying drawingsthat illustrate specific embodiments in which the invention can bepracticed. The embodiments are intended to describe aspects of theinvention in sufficient detail to enable those skilled in the art topractice the invention. Other embodiments can be utilized and changescan be made without departing from the scope of the invention. Thefollowing detailed description is, therefore, not to be taken in alimiting sense. The scope of the invention is defined only by theappended claims, along with the full scope of equivalents to which suchclaims are entitled.

In this description, references to “one embodiment,” “an embodiment,” or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment,” “an embodiment,” or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the current technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Embodiments of the invention provide systems and methods of capturingvideo data that adjust recording attributes of one or more video camerasto scan for a legible image of a license plate or other identifyingcharacters or markings on a vehicle. Further, embodiments of theinvention determine whether or not a legible image has been captured,and may take additional steps based on the determination. The additionalsteps may include rescanning the scene or storing the image data.

Turning to the figures, and particularly FIG. 1A, a first embodiment ofa recording system 10 is described. FIG. 1A includes an intermediaterecording device manager 12 (or “manager 12”), a vehicle recordingdevice 14 mounted in a police vehicle 16 (or other first responder'svehicle) and communicatively coupled (e.g., synced) to the recordingdevice manager 12, and a personal recording device 18. Personalrecording device 18 may be carried by a police officer 20 or other firstresponder and wirelessly synced to the recording device manager 12. Therecording device manager 12 is operable to detect when the vehiclerecording device 14, personal recording device 18, or any other synceddevice in range has started recording and to broadcast or transmit asignal to other synced recording devices in range, instructing recordingby the respective device. The recording device manager 12 may alsogenerate time stamps and unique serial numbers for a data recording, andcreate or collect metadata and transmit such time stamps, unique serialnumber, and metadata to the recording devices 14, 18 for corroboratingthe recorded data. For illustrative purposes, the recording system 10includes the vehicle recording device 14 and the personal recordingdevice 18, but it will be understood that duplicate or additionaldevices, such as audio recorders, thermal imagers, security cameras,radios, radar and LIDAR scanners, and electronic weapons, can be syncedto the recording device manager 12. Specifically, multiple recordingdevices 14, 18 can be synced with the manager 12 simultaneously.

In embodiments of the invention, the vehicle recording device 14 andpersonal recording device 18 are each video cameras operable to recorddata, including without limitation, audio data and video data. Moreover,the recording devices 14, 18 are also operable to record or generatemetadata associated with the recording, such that the data recorded bythe devices 14, 18 includes the audio data, the video data, and/or themetadata associated with either or both of the audio and video data.Examples of metadata for an audio or video recording include a location(as determined by a GPS) where the data was recorded, a user whorecorded the data or was otherwise associated with the recording device14, 18 (e.g., an officer driving a police vehicle or an officer wearingthe personal recording device 18), the time stamp and/or unique serialnumber, a trigger for the data recording event (e.g., what prompted adata capture scan by the recording devices), and other data related tothe recorded event. Additionally, as further discussed below, themetadata may include or link to data derived from identifying marks on asubject vehicle.

The recording device manager 12 is illustrated in FIG. 1A as astandalone device but can be incorporated into other devices, such as alaptop (including external computing device 22), a radio, a recordingdevice (including the vehicle recording device 14), a mobilecommunications device, a battery pack, or an electronic weapon. Therecording device manager 12 may be permanently or removably mountedanywhere in the police vehicle 16, such as on the dashboard, centerconsole, or windshield. Alternatively, the recording device manager 12can be carried or worn by the police officer 20, such as on his utilitybelt or in his pocket.

Exemplary hardware included in embodiments of the invention isillustrated in FIG. 1B. Computer 102 can be a laptop computer, asillustrated as external computing device 22 of FIG. 1A. Depicted withcomputer 102 are several components, for illustrative purposes. In someembodiments, certain components may be arranged differently or absent.Additional components may also be present. Included in computer 102 issystem bus 104, whereby other components of computer 102 can communicatewith each other. In certain embodiments, there may be multiple busses orcomponents may communicate with each other directly. Connected to systembus 104 is central processing unit (or “processor”) 106. Also attachedto system bus 104 are one or more random-access memory (RAM) modules.Also attached to system bus 104 is graphics card 110. In someembodiments, graphics card 104 may not be a physically separate card,but rather may be integrated into the motherboard or the processor 106.In some embodiments, graphics card 110 has a separategraphics-processing unit (GPU) 112, which can be used for graphicsprocessing. Also on graphics card 110 is GPU memory 114. A display 116may be connected (directly or indirectly) to graphics card 110 for userinteraction. In some embodiments no display is present, while in othersit is integrated into computer 102, or detached physically and remotelyconnected to computer 102. Similarly, peripherals such as keyboard 118and mouse 120 may be connected to system bus 104. Like display 116,these or other peripherals may be integrated into computer 102, remotelyconnected, or absent. Also connected to system bus 104 is local storage122, which may be any form of computer-readable media, and may beinternally installed in computer 102 or externally and removeablyattached.

Computer-readable media include both volatile and nonvolatile media,removable and nonremovable media, and contemplate media readable by adatabase. For example, computer-readable media include (but are notlimited to) RAM, ROM, EEPROM, flash memory or other memory technology,CD-ROM, digital versatile discs (DVD), holographic media or otheroptical disc storage, magnetic cassettes, magnetic tape, magnetic diskstorage, and other magnetic storage devices. These technologies canstore data temporarily or permanently. However, unless explicitlyspecified otherwise, the term “computer-readable media” should not beconstrued to include physical, but transitory, forms of signaltransmission such as radio broadcasts, electrical signals through awire, or light pulses through a fiber-optic cable. Examples of storedinformation include computer-useable instructions, data structures,program modules, and other data representations.

Finally, network interface card (NIC) 124 is also attached to system bus104 and allows computer 102 to communicate over a network. NIC 124 canbe any form of network interface known in the art, such as Ethernet,ATM, fiber, Bluetooth, or Wi-Fi (i.e., the IEEE 802.11 family ofstandards). NIC 124 may connect computer 102 to a local network,optionally via a CAN bus 26, as further described below. The localnetwork may in turn connected to Internet, or in some embodimentscomputer 102 may itself be directly connected to Internet.

Returning to FIG. 1A, external computing device 22 may be coupled torecording device manager 12 via wired or wireless connection. Theexternal computing device 22 can be a laptop, tablet, mobile device,smartphone, or other computing device. The external computing device 22displays a graphical user interface (GUI) by which the police officer 20or other user may view recorded data and make selections regarding therecording system 10. As further described below, external computingdevice 22 may function as an input/output device to allow an officer tojudge the legibility of characters captured in video data. Externalcomputing device 12 may include a central processing unit (CPU) and oneor more random-access memory (RAM) modules, as well as a graphics cardand display for user interaction. In some embodiments no display ispresent, while in others it may be spaced apart from and coupled to anexternal computing device 22. Similarly, peripherals such as keyboardand mouse may be coupled to external computing device 22. Like thedisplay, these peripherals may be integrated into external computingdevice 22 or absent. External computing device 22 may betouch-sensitive, allowing an officer to input data or make selectionsvia tap, swipe, or other gesture.

A power source 24 may be electronically connected to the vehiclerecording device 14 through dedicated wiring. The power source 24supplies power to each of the electronic components of the vehiclerecording device and, in embodiments of the invention, to the recordingdevice manager 12 and/or the personal recording device 18. Inembodiments of the invention, the power source 24 is the policevehicle's battery but can be another power source, such as a batterycartridge of the external computing device 22.

The electronic connection between the recording device manager 12, thevehicle recording device 14, and the personal recording device 18optionally includes a control area network (CAN) bus 26, which “directstraffic” for incoming and outgoing signals based on indicated importanceor other factors and follows an algorithm for determining the order inwhich (or whether) signals are transmitted.

The vehicle recording device 14 is operable to record audio, video,and/or other data. In some embodiments, the vehicle recording device 14is a video recording device such as one produced by Digital Ally, Inc.,including the DVM100, DVM250, DVM250Plus, DVM250Law, DVM400, DV440Ultra,DVM470, DVM500, DVM500Plus, and DVM750. As described below, in someembodiments the vehicle recording device 14 is operable to receive asignal of a triggering event, while in other embodiments the vehiclerecording device 14 utilizes the CAN bus 26 and is operable to receivetime stamps and metadata in addition to the signal of a triggeringevent. The vehicle recording device 14 can be incorporated into thepolice vehicle's rear view mirror, dashboard, spotlight, or otherlocations associated with the police vehicle 16 or may be a stand-aloneunit mounted within or on the police vehicle 16. The vehicle recordingdevice 14 may receive power from the power source 24 through dedicatedwiring. In addition to the exemplary vehicle recording devices listedabove, a vehicle recording device is further described in commonly-ownedU.S. Pat. No. 8,520,069, issued Aug. 27, 2013, entitled “Vehicle-MountedVideo System with Distributed Processing,” the entirety of which isincorporated by reference herein.

The personal recording device 18 is small, portable, wearable, easilyconcealed, and is operable to record audio, video, thermal, chemical, orother data. The personal recording device 18 can be worn by the officer20, such as on the officer's shirt, hat, eyeglasses or sunglasses,electronic weapon, breath analyzer, or other device accessed or used bythe officer. The personal recording device 18 is operable to receive asignal instructing the device 18 to begin or stop scanning (as discussedin further detail below), a signal indicative of a triggering event, andtime stamps and metadata corresponding to the recordings. Additionally,the personal recording device 18 may further include a clock fordetermining a time corresponding to when a particular item of data wasrecorded. An exemplary personal recording device is the “FIRSTVU HD”produced by Digital Ally, Inc. and further described in U.S. Pat. No.9,019,431, issued Apr. 28, 2015, and commonly assigned with the presentapplication, the entirety of which is hereby incorporated by referenceinto the present application.

Recordings generated by the recording devices 14, 18 and associatedmetadata may be temporarily or permanently stored in a local memoryelement (hereinafter “memory”), such as a memory of the particularrecording devices 14, 18, and/or a memory of external computing device22 located in the police vehicle 16. The recording devices 14, 18 mayalternatively or additionally be allowed to upload recordings to anexternal server or storage device. The external server or storage devicecould be a large-capacity storage device 28, such as a DVR housed in thevehicle, or may be a centralized computing device, such as housed at apolice precinct. These examples are not meant to be limiting; any formof data storage and duplication is intended within embodiments of theinvention.

An exemplary scenario of the recording system 10 in use is now describedfor illustrative purposes. The recording system 10 may be used by thepolice officer 20 to record video data during an event such as a trafficstop. The recording device manager 12 may be mounted near the vehiclerecording device 14, such as on the windshield of the police vehicle 16,or may be integrated within a housing of the vehicle recording device14. Alternatively, the recording device manager 12 may be mountedanywhere within the police vehicle 16 that allows for the recordingdevice manager 12 to communicate (either via a wired or wirelessconnection) with the vehicle recording device 14. In embodiments of theinvention, the vehicle recording device 14 is oriented in a forwarddirection relative to a front of the vehicle to record the traffic stop,and in yet further embodiments, multiple vehicle recording devices 14may be mounted in or on the vehicle and oriented in different directionsrelative to the vehicle, such as backwards towards a rear of thevehicle, and to the left and right sides of the vehicle. The personalrecording device 18 is mounted to the police officer's person or isotherwise carried by the police officer 20, such as on a lanyard, belt,or shoulder. In embodiments of the invention, the personal recordingdevice 18 may include a GPS, an RFID, or another type of location oridentification feature or sensor (not shown) that informs the recordingdevice manager 12 of the relational location of the personal recordingdevice 18 to the recording device manager 12. Alternatively, the officermay carry on their person a GPS (such as housed within or associatedwith a mobile communications device), RFID, or other type of location oridentification sensor. Recording system 10 may include additionalsensors not illustrated in FIG. 1A, such as a rangefinder. Datacollected from such sensors may be stored along with video, audio, andmetadata, and may be used in detection of trigger parameters ordetermination of scan range limits, as further discussed below.

Embodiments of the invention are not intended to be limited to thetraffic stop situation described above. Embodiments may be stationary ormobile camera systems employed by businesses to record the identity ofvehicles arriving and departing from a parking lot. Alternatively,embodiments may be employed in maritime settings, such as for trackingof shipping containers. In other embodiments of the invention, amilitary installation may use a camera system to pre-screen vehiclesapproaching a secure location. Any system including one or more videorecording devices that scan for a legible image of a marking on avehicle may fall within embodiments of the invention.

Returning to the law enforcement example, in embodiments of theinvention, the recording device manager 12 may activate a data capturescan (or simply “scan”) from vehicle recording device 14 and/or personalrecording device 18 responsive to a triggering event (also more simplyknown as a “trigger”). Examples of a triggering event may include, forexample, turning on the vehicle's siren and/or signal lights, anindication that the vehicle is parked, an electronic detection of asubject car or a license plate, an accelerometer measurement outside apre-established norm, a position of the vehicle and/or officer asmeasured by a GPS, a vehicle crash event, the police vehicle 16attaining a threshold speed (e.g., 80 m.p.h.), activation of anelectronic weapon, opening of the vehicle door, and/or activation of aradar or the radar detecting a subject car's speed at or over apre-determined speed. In embodiments, the recording device manager 12may receive a signal from, for example, the vehicle recording device 14,external computing device 22, or police vehicle 16 indicative of atriggering event. In response to receipt of the signal, or based on atype of triggering event as evidenced by the signal, the recordingdevice manager 12 may instruct recording by the vehicle recording device14 or the personal recording device 18 to begin a scan. As an exemplaryscenario, the recording device manager 12 may receive a signalidentifying a triggering event of a police vehicle 16 being placed inpark while the vehicle signal lights are activated. Upon receipt of thesignal, the recording device manager 12 sends a signal to either or bothof the vehicle recording device 14 or the personal recording device 18to instruct the devices 14, 18 to begin a scan. It should be appreciatedthat other types of triggering events and exemplary scenarios can beemployed.

Alternatively, a data capture scan may be activated manually based on auser's manual selection, for instance via a police officer's buttonpress of recording device manager 12, vehicle recording device 14, orexternal computing device 22. A manual selection may be made remotelyfrom a fob carried by police officer 20 or a control integrated into thestructure of personal recording device 18. In embodiments of theinvention, a manual selection may be made by a remote user, such as by adispatcher at a police station. As further discussed below, whetherinitiated via a trigger or via manual indication, a scan serves toadjust one or more recording attributes between a lower limit and upperlimit to search for a legible image of a license plate or other vehiclemarking.

FIGS. 2A-C illustrate examples of images captured by a recording devicesuch as vehicle recoding device 14 of a subject vehicle 200,204,208 witha license plate 202,210 during a typical traffic stop situationintroduced above. FIG. 2A illustrates a captured image of a subjectvehicle 200 during a traffic stop occurring on a clear day with idealrecording conditions. Factors such as the make, model, color, damage,decals, bumper stickers, etc. of vehicle 200 can be distinguished in thecaptured video data, as well as the actions of figures in the scene. Inparticular, the license plate 202 of vehicle 200 is legible. Under suchconditions, the license plate 202 will likely be clearly readable fromportions of the video data captured (which may be motion video and/orstill frames) by a human observer and/or a computer characterrecognition program.

FIG. 2B illustrates a similar situation to that illustrated in FIG. 2A,only in this instance the traffic stop is occurring at night, whenrecording conditions are less ideal. A subject vehicle 204 identical tovehicle 200 in FIG. 2A has been pulled over, and an image is capturedfrom vehicle recording device 14 mounted forward-facing in policevehicle 16. The subject vehicle 204 can again be distinguished byfactors such as make, model, color, etc., though perhaps to a lesserextent than in FIG. 2A. However, interference from sources such as theheadlights of police vehicle 16 reflecting from the rear 206 of subjectvehicle 204 has washed out the image of the license plate, making itcompletely illegible. This effect is known as “bloom,” and inhibits theability of a user or computer program to definitively determine theidentity of subject vehicle 204 from the recorded video data. As seen inFIG. 2B, the effect of bloom can be impactful enough to saturate therecording camera in region 206 of the image, such that the license platecannot be seen at all.

FIG. 2C illustrates the traffic stop situation a third time, againoccurring at night as in FIG. 2B. A subject vehicle 208 identical tovehicles 200,204 in FIGS. 2A-B has been pulled over, and an image iscaptured from vehicle recording device 14 mounted forward-facing inpolice vehicle 16. In illustrated image capture of FIG. 2C, one or morerecording attributes of vehicle recording device 14 have been adjustedsuch that the bloom effect of the reflected headlights has beenminimized. The subject vehicle 208 as a whole is actually much lessdistinguishable in terms of make, model, color, etc. compared to subjectvehicle 204 of FIG. 2B, but the critical information of license plate210 is legibly captured. The video data recording illustrated in FIG. 2Cmay be less likely to capture any events happening in the recorded scenebut is valuable for establishing proof of the identity of subjectvehicle 208.

Embodiments of the invention adjust one or more recording attributes ofone or more video recording devices, such as vehicle recording device 14or personal recording device 18, to scan for at least one frame of alegible image of markings on a vehicle, such as those on a licenseplate. As in the example illustrated in FIG. 2C, the frame containinglegible markings for which the recording devices are scanning may bedark, obscured, unfocused, or otherwise unclear with respect to anyelements of the scene other than the license plate (or other vehiclemarkings of interest). This is not intended to be limiting, as thelegible frame may present a clear view of all elements of the scene, asin FIG. 2A. Examples of recording attributes that may be adjustedinclude gain, shutter speed, focus, white balance, sharpness, backlightcompensation, iris aperture, or any other applicable adjustableattribute of the recording devices.

Because adjusting the recording attribute(s) of the recording devices14,18 to legibly capture the license plate 200,210 may reduce visibilityof other elements in the recorded scene, embodiments of the inventionmay not permanently set the recording attributes to such values. Doingso is unnecessary, as only a single legible frame is needed foridentification purposes. Additionally, permanent adjustment of therecording attributes might require significant computation to determinethe appropriate values and may render the recording less valuable as adocumentation of events in the scene. Rather, in embodiments of theinvention, selected recording attributes are only temporarily adjustedto scan for a legible image of a marking on a vehicle, such as a licenseplate. For example, a recording attribute such as gain may be adjustedacross a range of values, searching for a single value within that rangeat which the license plate is legible. In embodiments of the invention,one or more recording devices 14,18 perform a scan for legible markingson a vehicle while other recording devices 14,18 continue recordingvideo data using normal recording attributes. In this way the portion ofrecorded video occurring during the scan is recorded as usual. It shouldalso be appreciated that embodiments of the invention may employ adedicated vehicle recording device 14 for capturing the image orscanning the vehicle for markings.

The scan range for a particular attribute includes a lower limit and anupper limit, each of which may be a predetermined limit programmed intomemory, may be selected manually by a user, or may be dynamicallyselected by the recording system 10 based on factors such as the time ofday, a sensed ambient light level, or a distance measurement. Such adistance measurement may be, for instance, from the recording device14,18 to the subject vehicle 200. Alternatively, a distance measurementmay be estimated by an officer 20 and entered via external computingdevice 22. Manual selections may be presented to the user as multiplechoice selections based on the user's evaluation of the visibility ofthe scene, such as a “low-light” scan range, “high interference” scanrange, or “long distance” scan range. These scan ranges are meant onlyas examples, and are not intended to be limiting in any way.

A recording attribute may be adjusted within a scan range by acontinuous “sweep” of the scan range or may be adjusted incrementally byset values. The incremental values by which a recording attribute isadjusted may be uniform increments, which may be predeterminedincrements programmed into memory or may be selected manually by a user.Alternatively, uniform increments may be dynamically selected by therecording system based on sensed parameters such as the time of day, asensed ambient light level, or a distance measurement. Like the scanrange limits, the increments of adjustment of a recording attributewithin a scan range may be presented to the user as multiple choiceselections based on their evaluation of the visibility of the scene,such as “low-light” adjustments, “high interference” adjustments, or“long distance” adjustments. Again, these are meant only as examples,and are not intended to be limiting in any way.

In the course of performing a scan for a legible marking on a vehicle,embodiments of the invention may adjust more than one recordingattribute within respective scan ranges, each scan range including arespective upper and lower limit. For example, a scan may adjust gainbetween a minimum level of 30% and a maximum level of 70% and alsoadjust shutter speed between 0.02 and 0.05 seconds. The adjustments maybe done simultaneously, or may be performed independently of oneanother, with the value of one recording attribute adjusted while theother is held at a static value. Specifically, a first recordingattribute may remain at a first value within its first scan range whilea second recording attribute is adjusted within its second scan range,and the second recording attribute may remain at a second value withinits second scan range while the first recording attribute is adjustedwithin its first scan range.

In some embodiments, the value of a given recording attribute may beadjusted throughout a scan range multiple times, with the values ofother recording attributes held at different static values each time.For instance, gain may be adjusted between a 30% lower limit and a 70%upper limit while the shutter speed is held at 0.025 seconds, and thenadjusted again between the same limits while the shutter speed is heldat 0.05 seconds. The shutter speed may then be adjusted one or moretimes while the gain is held at one or more static values. Static valuesmay be predetermined, selected by a user, or determined dynamically bythe system upon initiation of a scan. The above examples are notintended to be limiting. In embodiments of the invention, more than tworecording attributes may be adjusted simultaneously or independentlywhile other recording attributes are held static. Specifically, a scanmay include a third scan range including a third upper limit and a thirdlower limit. For example, a single scan may adjust shutter speed, gain,and white balance between upper and lower limits. Any combination ofincrements, selected type and number of recording attributes, upper andlower limits, and independence or simultaneity of adjustments areintended within embodiments of the invention.

In embodiments of the invention, representative image captures from ascan may be presented to a user on a display, as illustrated in FIG. 3.As discussed below, a user may respond to one or more images presentedon the display via touch or through a separate input device to indicatesuccess or failure of the scan and/or select further steps to beperformed. FIG. 3 is intended only as an illustration of a displaypresented in embodiments of the invention, and is not intended to belimiting.

FIG. 4 broadly illustrates steps performed in operation of an embodimentof the invention. These steps may be performed during an event such as atraffic stop, where a video recording of a subject vehicle 200,204,208needs to capture a legible image of a license plate 202,210. Prior tostep 402, one or more recording devices 14,18 may or may not already beactive, recording, and/or storing video data. At step 402, an indicationto begin a scan is provided to the system. As discussed above, thisindication to begin may be provided by a user's manual input or based onone or more sensed trigger parameters. In some embodiments, theindication to begin a scan may activate one or more recording devices14,18 and/or cause them to temporarily or permanently store video data.In response to the received indication, a scan is initiated by thesystem based on a program stored in memory, user input, and/or sensedparameters. At step 404, a first recording attribute, such as gain, isadjusted between within a first scan range. The first scan range isbound by an upper limit and a lower limit, which may be predetermined,based on sensed parameters, or manually selected by a user. While thefirst recording attribute is being adjusted, all other recordingattributes may be held at selected values. The selected static valuesfor each recording attribute not being adjusted may be predetermined,based on sensed parameters, or manually selected by a user. At step 406,the first recording attribute is held at a static value while a secondrecording attribute, such as shutter speed, is adjusted within a secondscan range. Again, while the second recording attribute is beingadjusted, all other recording attributes may be held at selected values,which again may be predetermined, based on sensed parameters, ormanually selected by a user. In embodiments of the invention, thesesteps may be preformed for three or more recording attributes withintheir respective scan ranges. Further, the adjustment of each recordingattribute within their respective scan ranges may alternatively beperformed simultaneously, to achieve a faster (though possibly lessrobust) scan.

At step 408, a determination is made as to whether or not markings on avehicle, such as those appearing on a license plate, have been legiblycaptured. In embodiments of the invention, representative frames from ascan may be presented via a display (such as on external computingdevice 22) for confirmation and/or selection by a user. As seen in FIG.3, in embodiments of the invention a display screen 300 is presented toa user with frames 304, 306, and 308 selected from a scan. Frame 304 hasthe clearest image of the vehicle, but has no legible license plate dataas explained in relation to FIG. 2B. Frames 306 and 308 have dark,blurry, or otherwise obscured images of the vehicle, but havesuccessfully captured the license plate data needed for identification.A user may respond to these displayed frames 304,306,308 via touchingthe screen or use of a separate input device to select one or more thatinclude legible data. For instance, an officer 20 may select frames 306and 308, indicating that the license plate 123XYZ is legible in each ofthese frames. Next, the officer may tap button 310 in response window302 to store the selected frames in memory, associated with the videodata captured of the traffic stop event. A text recognition program maythen extract the data from one or more of the selected frames. At thispoint, the system proceeds to step 410 in which data from the licenseplate may be saved, possibly as metadata relating to the captured videodata. For instance, the title of the stored video may be appended withthe recognized license plate data. Additionally or alternatively,metadata related to the captured video data may include a link to astill image of the license plate data stored in memory.

FIG. 3 further includes buttons 312 and 314 in response window 302, aswell as timer 316. Button 312 may be pressed by an officer 20 toindicate that a scan should be cancelled. This may be of use, forexample, in case a traffic stop is uneventful or another officer hasalready documented the scene. Selection of button 312 may allow a userto rescan the scene if none of the frames 304,306,308 have legiblycaptured the license plate data. Selection of Rescan button 312 mayinitiate a modified scan, as further described below. Finally, FIG. 3displays a timer 316, indicating a remaining amount of time before atimeout occurs. The total amount of time allowed before timeout may beprogrammed into memory or set by the user. Upon expiration of timer 316,the system may automatically cancel the scan, rescan, or initiate amodified scan. Alternatively, upon timeout the system may proceed tostep 410, storing all of the displayed frames 304,306,308 in memory.

In other embodiments, step 408 may be performed initially by a computertext recognition algorithm. The algorithm may select representativeframes from the scan and extract text from each frame, searching for astring of text that fits the appropriate format of a license plate.Alternatively, the algorithm may run continuously during the scan, andmay halt the scan upon recognition of a string of characters in a validformat, such as in a license plate format. Valid formats may be storedin memory. In embodiments of the invention, the computer-recognizedscreen may be presented to a user along with an image frame from whichit was extracted for user confirmation of successful license platecapture. At this point, the system proceeds to step 410 in which datafrom the license plate may be saved, possibly as metadata relating tothe captured video data.

As has been described above, computer and/or user determination ofsuccessful capture of a legible image of a marking on a vehicle mayinitiate storage of at least a portion of the scan that includes thelegible marking. However, in the event that capture of a legible imageis determined to be unsuccessful, the system may perform an additionalscan. The additional scan may activate automatically or in response toselection by a user. The additional scan may use recording attributes,scan ranges, and adjustment increments that are identical to those ofthe prior scan(s). Alternatively, the additional scan may be a modifiedscan, differing from the prior scan(s) in any or all of these elements.

A modified scan may be beneficial in situations with particularlydifficult viewing conditions to provide an increased likelihood ofcapturing a legible image of a marking on a vehicle. The modified scanmay simply select one or more different recording attributes foradjustment, such as gain and frame rate rather than white balance andfocal distance. The modified scan may adjust the same recordingattributes, but choose different upper and/or lower limits, modifyingthe scan range of one or more of the recording attributes. Modifiedupper and lower limits may define a larger scan range in a modified scanfor a particular recording attribute, and/or may shift the original scanrange. A modified scan may alternatively or additionally change thesimultaneity of adjustment of recording attributes. For example, if in aprevious failed scan, gain and white balance were adjusted within theirrespective scan ranges simultaneously, in a subsequent modified scangain may be held at a static value while white balance is adjusted andvice versa. Any or all of the modifications discussed may be employed ina given modified scan, as well as any other modifications not expresslydescribed.

While reference has been made above to the various components andtechniques of embodiments of the invention, the description that followswill provide further examples systems and processes that may be added inembodiments of the invention. The description below is intended tomerely exemplify steps that may be taken in practice of operation ofembodiments of the invention and is not intended to be limiting. Furthersteps that may be performed in practice of some embodiments of theinvention are illustrated in FIGS. 5A-C and herein described.

FIG. 5A begins at step 502, corresponding to step 402 of FIG. 4, inwhich an indication to begin a scan is provided to the system by a humanor computer. The indication may be in response to one or more triggerparameters such as an indication that a police vehicle 16 is parked, acomputer detection of a subject car, a detection of a license plate 200,an activation of a vehicle siren, and an activation of signal lights. Atstep 504, the lower and upper limits of the first scan range aredetermined for a first recording attribute. These limits may bepredetermined, selected by a user, or determined dynamically based onsensed parameters such as a sensed light level. At step 506 the systemdetermines whether or not the first recording attribute will be adjustedby uniform increments. If the increments are uniform, the processproceeds to step 508, at which the system determines whether the size ofthe uniform increments has been predetermined and stored in memory, orif the size needs to be determined based at least partially on sensedfactors. If they are predetermined, the system proceeds to step 510,adjusting the first recording attribute between the first upper andlower limits using the uniform increments. If sensed factors must betaken into account, the system does so at step 512 before proceeding tothe adjustment at step 510.

Returning to step 506, if the increments of adjustment are not uniform,the process proceeds to step 514, at which the system determines whetheror not the system should perform a continuous sweep through across thescan range. If this determination is yes, the system adjusts the firstrecording attribute in this way at step 516. If the determination atstep 514 is no, the system adjusts the first recording attribute using aset of predetermined or random non-uniform increments at step 518.

Each of these regimes of adjustment of the first recording attributeconverge at step 520, at which the preceding process (beginning at step504) is performed once again, this time with respect to the secondrecording attribute. In step 520, as in step 504, the system determinesthe upper and lower limits for the second scan range, corresponding tothe second recording attribute. Again in steps 522, 524, 528 and 530(FIG. 5B), determinations are made about how the second recordingattribute is to be scanned within the second scan range. Each of thesedeterminations are made in the same manner as the decision points atsteps 506, 508, and 514, resulting in adjustment of the second recordingattribute at steps 526, 528, or 534. The determinations made foradjustment of the second recording attribute may or may not be the sameas those made for the first recording attribute. For example, the firstrecording attribute may be gain, adjusted by 1% increments from 50% to100%, while the second recording attribute, may be white balance,adjusted continuously from the minimum to maximum white balanceavailable to the system. This is meant only as an example, and is notintended to be limiting. Any combination of recording attributes, scanranges, and scan regimes is intended to be within embodiments of theinvention.

Specifically, at step 520, the lower and upper limits of the second scanrange are determined for a second recording attribute. These limits maybe predetermined, selected by a user, or determined dynamically based onsensed parameters such as a sensed light level. At step 522 the systemdetermines whether or not the second recording attribute will beadjusted by uniform increments. If the increments are uniform, theprocess proceeds to step 524, at which the system determines whether thesize of the uniform increments has been predetermined and stored inmemory, or if the size needs to be determined based at least partiallyon sensed factors. If they are predetermined, the system proceeds tostep 526, adjusting the second recording attribute between second firstupper and lower limits using the uniform increments. If sensed factorsmust be taken into account, the system does so at step 528 beforeproceeding to the adjustment at step 526.

Returning to step 522, if the increments of adjustment are not uniform,the process proceeds to step 530, at which the system determines whetheror not the system should perform a continuous sweep through across thesecond scan range. If this determination is yes, the system adjusts thesecond recording attribute in this way at step 532. If the determinationat step 530 is no, the system adjusts the second recording attributeusing a set of predetermined or random non-uniform increments at step534.

Regardless of the determinations made, all of these regimes ofadjustment of the second recording attribute converge at step 536. Atthis step the system determines whether or not a third attribute is tobe adjusted within a third scan range. If so, the process proceedsthrough steps 538, 540, 542, 544, 546, 548, and 550 for determining themethod of adjusting the third recording attribute. These steps areperformed in the same manner as previously performed for the first andsecond recording attributes. These steps may be repeated for anarbitrary number of recording attributes, as determined by the systemand/or a user.

Specifically, at step 540, the lower and upper limits of the third scanrange are determined for a third recording attribute. These limits maybe predetermined, selected by a user, or determined dynamically based onsensed parameters such as a sensed light level. At step 542 the systemdetermines whether or not the third recording attribute will be adjustedby uniform increments. If the increments are uniform, the processproceeds to step 544, at which the system determines whether the size ofthe uniform increments has been predetermined and stored in memory, orif the size needs to be determined based at least partially on sensedfactors. If they are predetermined, the system proceeds to step 546,adjusting the third recording attribute between the third upper andlower limits using the uniform increments. If sensed factors must betaken into account, the system does so at step 548 before proceeding tothe adjustment at step 546.

Returning to step 542, if the increments of adjustment are not uniform,the process proceeds to step 550, at which the system determines whetheror not the system should perform a continuous sweep through across thethird scan range. If this determination is yes, the system adjusts thefirst recording attribute in this way at step 552. If the determinationat step 550 is no, the system adjusts the third recording attributeusing a set of predetermined or random non-uniform increments at step554.

When the final recording attribute has been adjusted (which in the caseof FIG. 5C is the third recording attribute) the system proceeds to step554, where a determination is made of the legibility of the captured bythe scan. This may be determined by a user in step 556. For example, thesystem may display one or more captured images of markings to a user forconfirmation of success. Alternatively, computer text-recognitionsoftware may independently determine the success or failure of the scan.Via either approach, if in step 558 the system determines a successfulcapture of a legible image of markings on a vehicle, a portion of thescan including the markings is stored in memory at step 560. If,however, in step 558 the system determines an unsuccessful capture of alegible image of markings on a vehicle, the system proceeds to step 562to determine whether an additional scan should be performed. This stepmay be performed automatically by the system or in response to userinput. Determination of initiation of an additional scan by a user maybe subject to a timeout, as described above. If an additional scan isrejected at step 562, the system quits at step 564, returning to itsinitial condition of waiting for an indication to begin a scan. If anadditional scan is initiated at step 562, the system returns to step 502to repeat the entire process. The additional scan may be identical tothe first or may be a modified scan, differing in number or type ofrecording attributes adjusted, methods of adjustment, and/or scan rangesas described above.

It should be appreciated that, while the above disclosure is directedmainly to the field of law enforcement, some embodiments of theinvention may be employed for any pursuit requiring legible videocapture of information. Embodiments of the invention may be used in anysetting or field, such as military or road maintenance vehicles, tomaximize the likelihood of capturing a legible image of readablecharacters using a video camera. In embodiments of the invention,readable characters may be identified from sources other than licenseplates, such as billboards, street signs, bumper stickers, or apparel.Further, though the description above is uses a car as subject vehicle200,204,208, embodiments of the invention could equivalently be employedto identify a subject boat, trailer, motorcycle, etc. Embodiments of theinvention may be used by private individuals or businesses to helpprevent fraud, identify visitors, or track shipments. The lawenforcement field discussed is merely exemplary and should not beconstrued as limiting.

Having thus described various embodiments of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:
 1. A method of scanning for a legible marking on avehicle, the method including the steps of: scanning using a videocamera, wherein the video camera has at least one recording attribute;sweeping the at least one recording attribute across a scan range byuniform increments, wherein the scan range is defined by a lower limitand an upper limit, determining a size of the uniform increments basedon at least one of a time of day and a sensed ambient light level;determining, after said sweeping of said at least one recordingattribute, that the legible marking on the vehicle has been capturedbased at least in part on a user's response to a displayed image of atleast a portion of the vehicle.
 2. The method of claim 1, wherein the atleast one recording attribute is a first recording attribute and thescan range is a first scan range, and further comprising the step of:sweeping a second recording attribute across a second scan range,wherein the second scan range is defined by a second lower limit and asecond upper limit.
 3. The method of claim 2, wherein said firstrecording attribute remains at a first static value within said firstscan range while said second recording attribute is swept across saidsecond scan range, and wherein said second recording attribute remainsat a second static value within said second scan range while said firstrecording attribute is swept across said first scan range.
 4. The methodof claim 2, further comprising the step of: sweeping a third recordingattribute across a third scan range, wherein the third scan range isdefined by a third lower limit and a third upper limit.
 5. The method ofclaim 4, wherein the first recording attribute is gain, the secondrecording attribute is shutter speed, and the third recording attributeis aperture.
 6. The method of claim 1, further comprising the step ofselecting said upper limit and said lower limit based on at least one ofthe time of day and the sensed ambient light level.
 7. The method ofclaim 1, further comprising storing the displayed image with a videorecording.
 8. The method of claim 7, wherein the video recording isassociated with metadata comprising at least one of location data, atime stamp, and a serial number.
 9. An image capture system including: avideo camera with at least one recording attribute; and a processorconfigured to perform the steps of: scanning using the video camera;selecting a lower limit and an upper limit based on at least one of atime of day and a sensed ambient light level; sweeping the at least onerecording attribute across a scan range, wherein the scan range isdefined by the lower limit and the upper limit; determining, after saidsweeping of said at least one recording attribute, that a legiblemarking on the vehicle has been captured based on a computer recognitionof a valid marking.
 10. The image capture system of claim 9, furthercomprising a storage device for storing an image of the legible markingwith metadata associated with the image.
 11. The image capture system ofclaim 9, wherein the video camera is a personal recording device worn bya law enforcement officer.
 12. The image capture system of claim 9,wherein the video camera is a vehicle recording device mounted in a lawenforcement vehicle.
 13. The image capture system of claim 9, furthercomprising a display for displaying an image of the captured legiblemarking to a user.
 14. A method of scanning for a legible marking on avehicle, the method including the steps of: scanning using a videocamera, wherein the video camera has at least one recording attribute;selecting a lower limit and an upper limit based on at least one of atime of day and a sensed ambient light level; sweeping the at least onerecording attribute across a scan range, wherein the scan range isdefined by the lower limit and the upper limit; determining, after saidsweeping of said at least one recording attribute, that the legiblemarking on the vehicle has been captured based on a computer recognitionof a valid marking format.
 15. The method of claim 14, wherein therecording attribute is swept across the scan range by uniformincrements.
 16. The method of claim 15, further comprising the step ofdetermining a size of the uniform increments based on at least one ofthe time of day and the sensed ambient light level.
 17. The method ofclaim 14, further comprising the step of initiating a second scan upon adetermination that the marking on the vehicle has not been legiblycaptured.
 18. The method of claim 17, wherein the second scan sweeps therecording attribute across a modified scan range that is not identicalto the scan range.
 19. The method of claim 14, further comprising thestep of extracting and storing textual data from the legible marking.20. The method of claim 19, wherein the textual data from the legiblemarking is stored in metadata associated with a video recording.